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Protection of Underlying Structure in the Parylene or Polymer Patterning Process

IP.com Disclosure Number: IPCOM000045925D
Original Publication Date: 1983-May-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 3 page(s) / 44K

Publishing Venue

IBM

Related People

Yeh, JT: AUTHOR

Abstract

Oxidizable areas uncovered during oxygen plasma patterning of (poly) para-xylylene film are protected by photoresist where oxidation might become a source of problems.

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Protection of Underlying Structure in the Parylene or Polymer Patterning Process

Oxidizable areas uncovered during oxygen plasma patterning of (poly) para- xylylene film are protected by photoresist where oxidation might become a source of problems.

Para-xylylene polymer (parylene) thin films may be used as insulating or passivating coatings. The usage of the material sometimes requires that it be patterned in proper dimensions by oxygen plasma etching. After the end-point detection, the etching process usually continues for a certain amount of time (depending on the etch rate) to ensure complete etch-through for all areas. The underlying layer in the area of the developed hole, therefore, is exposed to the oxygen plasma. In many applications, this exposure to oxygen plasma does not impose any problem because the oxygen plasma usually does very little physical damage to the surface. However, there may be applications where this exposure is not desirable; the base material may be a metal layer and another metal layer is to make contact through a hole developed through the parylene film. The oxygen plasma can grow a thick layer of metal oxide; an additional oxide-removal process has to be implemented prior to the deposition of the contact. There may also be cases where the underlying material interacts with the oxygen plasma. In these situations, it is desirable that the underlying layer not be exposed to the oxygen plasma.

The other problem associated with etching polymers in oxygencontaining plasma is the possible backscattering of mask or electrodematerial onto the unmasked polymer. If the backscattered material has a much lower etch rate, then the backscattered material acts like a mask, causing residue to be left in the etched area, or causing incomplet...